Water treatment knowledge for Hong Kong, researched and referenced
Technical education for Hong Kong building owners and engineers. Researched and referenced — every article answers one real question and cites its primary sources.
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Legionella and the EMSD rules, water chemistry, tower operation, the economics of treatment, pool care and reference tools. Pick a topic to filter the articles, or read them all.
Showing 23 of 23 guides and tools
The real cost of doing nothing
Why a HK$100k dosing system looks expensive and a HK$5m pipe replacement does not. With an NPV calculator.
Legionella in water systems
Where it comes from, why cooling towers are the classic source, and what genuinely controls it.
Effects of pH on various biocides
Why the same dose of chlorine works at pH 7 and fails at pH 8.5 — and which biocides do not care.
Metal corrosion in water systems
Why pipework rots from the inside, the forms it takes, and what treatment is really doing.
Legionella and cooling tower compliance
What the EMSD Code of Practice requires, and where the 10 and 1,000 cfu/mL thresholds sit.
How often should a cooling tower be cleaned?
Cleaning, desludging and disinfection frequency for Hong Kong buildings.
The EMSD Code of Practice, in plain English
The water quality table, the Legionella action ladder, cleaning frequency and the record-keeping rules — from the actual 2023 Code.
Biofilm in cooling water systems
Why your chlorine residual reads fine and your bacteria counts do not, and why Legionella hides inside amoebae.
Cycles of concentration, explained
The number that decides how much water your tower wastes — and why you cannot simply turn it up. With a calculator.
The Langelier Saturation Index, explained
The most widely used number in cooling water, the five things it cannot see, and a live LSI calculator.
Pool water balance: pH, alkalinity, hardness
Why pH 7.2–7.8 matters, what alkalinity and hardness actually do, and the target ranges that stop chlorine being wasted.
Chlorine tablets vs liquid chlorine
Trichlor tablets or sodium hypochlorite? Strengths, pH effects, stabiliser build-up and which fits your pool.
Cyanuric acid and chlorine lock
What pool stabiliser does, why it accumulates with tablet chlorine, and why dilution is the practical fix.
Why your pool smells of chlorine
A strong pool smell often comes from chloramines. Learn what to test and how water treatment and ventilation help.
How to choose a cooling tower contractor
Seven things to demand from any Hong Kong water treatment contractor, the questions to ask, and how to compare quotations.
Restarting a tower after shutdown or typhoon
Why stagnant warm water breeds Legionella, and the restart sequence — inspect, clean, disinfect, verify, sample, document.
EMSD sampling results, tracked
Selected EMSD cooling tower sampling statistics, with dated official sources and a plain-English reading of the numbers.
Water treatment glossary (EN/繁)
45 water treatment terms with Traditional Chinese equivalents and plain-English definitions, A–Z.
Cooling tower compliance checklist
The printable one-page duty-holder checklist: the three Legionella bands, the recurring duties, and a monthly tick grid for the plant room.
Swimming pool licences: what the licence requires
Who needs an FEHD swimming pool licence in Hong Kong, the water-quality and testing conditions attached, and what to keep on file.
Fresh water tanks after a typhoon or flooding
How storms contaminate roof tanks, the warning signs, and the inspect → test → disinfect → re-test → document decision path.
How often should a water tank be cleaned?
WSD recommends cleaning at least every three months — when to clean sooner, and what a proper tank clean includes.
What does cooling tower water treatment cost?
What drives the price in Hong Kong, what a maintenance contract quotation must itemise, and what cheap quotes leave out.
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